It is known that sensors can track brainwave activity (electroencephalography, or EEG) and eye movement activity (electrooculography or EOG) and overt body movements during the night. Dreams typically occur during tonic and/or phasic Rapid Eye Movement (REM) and sometimes during deep sleep (Non-REM2 (N2) or N3). See AASM Manual for the Scoring of Sleep and Associated Events, Amer. Academy of Sleep Medicine, 2007 Westchester, Ill.; see also Rechtschaffen A, Kales A, editors. Los Angeles: Brain Information Service/Brain Research Institute, University of California; 1968 (manual of standardized terminology, techniques and scoring system of sleep stages in human subjects). Slow wave sleep, characterized by high amplitude low frequency brain activity, is also responsible for dreams during which the user may be stimulated to enhance dreams or quality of sleep.
Sleep experts score sleep by sampling a user's EEG in 30 second epochs. Experts classify an epoch as one of the following stages of sleep or awake: nonREM 1 (lightest sleep N1), nonREM 2 (medium sleep N2), nonREM 3 (deep sleep N3), and REM. REM sleep is further split into phasic REM (where bursts of eye moments occur) and tonic REM. A sleep cycle generally lasts 90 minutes and a typical sleep cycle stage sequence is: N1, N2, N3, N2, N1, REM, repeat.
REM is the primary sleep stage of interest to users for dream enhancement, where dream enhancement refers to applications including but not limited to the presentation of subtle stimuli towards the subconscious modulation of dream content, or loud and overt dream signs, towards the goal of assisting lucid dreaming, also known as an EILDs (externally-induced lucid dreams). A lucid dream occurs when one becomes aware that they are dreaming. Lucid dreaming has been proven to improve quality of life through reducing nightmare frequency, stress and anxiety and also allows users to practice real life tasks in the dream world towards their improvement in waking life. See Spoormaker V, I, van den Bout 3, “Lucid Dreaming Treatment for Nightmares: A Pilot Study” Psychother Psychosom 2006; 75:389-394; see also Spoormaker V, “A Cognitive Model of Recurrent Nightmares,” International Journal of Dream Research 2008; Vol 1, No 1; and see Erlacher, D., & Schredl, M. (2010), “Practicing a motor task in a lucid dream enhances subsequent performance: A pilot study,” Sport Psychologist, 24(2), 157-167 and “Applied Research Practicing a Motor Task in a Lucid Dream Enhances Subsequent Performance: A Pilot Study.” Eye movements are not affected by sleep paralysis and sleep scientists first used pre-agreed upon eye movements to prove the existence of the lucid dream state. Laberge, S. (1980), “Lucid dreaming: An exploratory study of consciousness during sleep,” (Ph.D. thesis, Stanford University, 1980), (University Microfilms No. 80-24, 691).
U.S. Pat. No. 8,628,462 to Berka discloses a system for optimizing sleep patterns. EEG signals are monitored. REM and NREM sleep stages are identified. Pattern recognition techniques are used to identify these sleep states. Once the current sleep state is detected, and the current sleep state differs from the desired sleep state, then stimuli is applied to the user. An accelerometer is used to detect major physical movement of the user.
U.S. Patent Publication No. 2013/0303837 to Berka discloses a system for tailoring sleep architecture. The Berka '837 published application is a further enhancement to the system described in the Berka '462 patent. The system includes a mask to be worn by a user. The mask has one or more electroencephalograph (EEG) sensors, a visual element configured to generate light, an audio element configured to generate sound, and a sensor determine a current sleep state and a target sleep state.
U.S. Pat. No. 5,954,629 to Yanagidaira shows EEG sensors used to detect brain waves and to electrically stimulate such brain waves. U.S. Pat. No. 5,507,716 to La Berge discloses equipment used to provide low level sensory stimuli to a sleeping person so that he or she may become consciously aware that he or she is dreaming, while he or she continues to sleep and dream, thereby having lucid dreams. The system includes means to detect the eyelid movements; a low intensity light and sound stimuli; a face mask adapted to be worn by the sleeping person; and a data storage to receive signal data from the sensors and generate the light and sound signals.
U.S. Pat. No. 7,727,139 to Topp discloses a dream detection system having: a mask with an infrared sensor to detect REM sleep; an alarm to indicate REM sleep; a first transmitter; a first receiver; and a first processor in data communication with the sensor, alarm, mask transmitter, and mask receiver; and a control unit which is separate and distinct from the mask. The control unit has a transmitter for transmitting data to the mask receiver; a receiver for receiving data from the mask transmitter; an audio player; a speaker; and a sensor detecting REM sleep.
U.S. Pat. No. 8,267,851 to Knoll discloses an apparatus that induces a lucid dream in the brain of a subject. The circuit generates a brain state entrainment signal sufficient to cause a lucid dream in the brain of the subject by entrainment. A transducer applies electrical signals to the user's brain. The transducer uses an electrical waveform, a light waveform, and a sound waveform and a magnetic waveform. The brain state entrainment signal from the circuit applies the transducer waveform to the subject while the subject is awake.